Recently, more and more three dimensional display devices concerning a flat panel display such as a liquid crystal panel have been offered. Regarding three dimensional display devices using flat panel display, a focus of attention has been on a three dimensional display device that achieves three dimensional viewing by spatially separating and displaying a plurality of images having both-eye parallax on left and right eyes using a lenticular lens or a parallax barrier. This device is advantageous in that an observer does not need any special glasses to view a three dimensional image (e.g., refer to Nonpatent Literature 1).
There has also been offered a pseudo three dimensional display device that uses a tactile display including an image display unit and an aerial ultrasonic phased array (refer to Nonpatent Literature 2). The three dimensional display device described in Nonpatent Literature 2 uses an image display device described in Patent Literature 1 as the image display unit for displaying a pseudo three dimensional image.
FIG. 1 is a schematic view showing the configuration of a three dimensional display device related to the present invention. As shown in FIG. 1, light emitted from image display unit 1001 is reflected by half mirror 1002. Then, an image is formed on concave mirror 1003, and aerial optical image 1004 is formed as a pseudo three dimensional image. In this case, fingertip position 1007 of the observer is detected by finger position sensor 1005, an image displayed on image display unit 1001 is updated according to fingertip position 1007 detected by finger position sensor 1005, and ultrasonic image 1008 from ultrasonic actuator array 1006 is provided in synchronization with aerial optical image 1004. This enables the observer to have an experience in which a visual sensation and a tactile sensation are combined without wearing any special devices.